This application claims a priority based on German application 199 26 346.9 filed on Jun. 9, 1999, and the disclosure in that German priority application is incorporated by reference herein.
This invention relates to a headlamp, in particular for motor vehicles, which has a headlamp housing that can be inserted into an opening in a vehicle body from a front, relative to a driving direction.
For pedestrian safety as it relates to automobiles, it is important in crash situations to conform to biomechanical limit values for specific parts of the human body when there is a collision. This also applies to an area of the headlamps which is subjected to loading primarily in the driving direction.
DE 197 32 301 A1 discloses a headlamp for a motor vehicle which has a headlamp housing that has at least one lamp device and which can be inserted into a housing receiver from a front relative to a driving direction. The housing receiver part is structured-as an energy absorbing deformation part to absorb impact energy that is transmitted primarily in the vehicle""s longitudinal direction. The housing receiver part of this known headlamp is structured as a deformation part in the form of a cylindrical cavity, on whose inner wall are welded two U-shaped energy absorbing elements, located across from one another and extending in the vehicle""s longitudinal direction, which serve simultaneously as guides for a headlamp housing on which pins are arranged for insertion into these guides.
Disadvantageous on the known headlamp is that the entire housing receiver is designed as an energy absorbing deformation part that absorbs impact energy transmitted in the vehicle""s longitudinal direction. This leads to a situation in which it is either very difficult to meet biomechanical limit values or to achieve adequate stability of the housing.
Therefore, it is an object of this invention to improve a known headlamp so that in collisions with pedestrians, prescribed biomechanical values for corresponding parts of the human body can be conformed to even with a high degree of stability of the headlamp.
According to principles of this invention, a headlamp housing of a headlamp, which is insertable into a vehicle body opening from a front relative to a driving direction, can be displaced along a predetermined energy-absorption path when an impact force occurs that effectively acts from the front in a direction at an acute angle to the longitudinal axis of the headlamp housing.
The housing receiver can have a generally sufficient stability because the headlamp housing can be displaced along the predetermined energy-absorption path. Favorable biomechanical limit values can be achieved through design of the predetermined energy-absorption path.
In a preferred embodiment of the invention the headlamp housing is enclosed in a receiver cavity of an energy absorbing block, whereby a backside and/or several sidewalls of the headlamp housing have direct surface contact with walls defining the receiver cavity. In this way an impact force can be captured from any direction from the front and can be suitably absorbed. In this case the headlamp housing can be displaced in a direction of impact force or the energy absorbing block can have regions of different stiffness such that the headlamp housing is guided in a prescribed direction within an opening in the vehicle body. Another advantage of the construction of an energy absorbing block that encloses or captures the headlamp housing is that this block has a supportive function for the headlamp housing, so that assembly related costs can be reduced. The number of attachment points of the headlamp housing can thereby be reduced or limited to specific areas.
According to a preferred embodiment of the invention the headlamp housing has guide parts which can be latched into guides of a housing receiver in a normal position. The guide parts are structured as pins, or lugs, which have a predetermined breaking point so that they shear off when a defined impact occurs and unlatch the headlamp housing within the housing receiver.
It can be assured that energy absorption displacement will be enabled in the event of a defined impact, in that the guide parts are structured as pins which have the predetermined breaking point.
According to a further preferred embodiment of the invention, a rear side of the headlamp housing, facing away from a light-transmissive protective cover, after freeing, can be pushed along the energy-absorption path against an energy absorber.
Because the rear side of the headlamp housing can be pushed against, or impacts with, an energy absorber, a precise predictable energy absorption is possible.
According to another preferred embodiment of the invention at least one sidewall of the headlamp housing is supported, via an energy absorber and a stationary holding part, preferably a housing receiver, which is rigidly attached to a vehicle body part so that when an impact occurs from the front a defined energy absorption path can be structured in a lateral direction.
According to another preferred embodiment of the invention the energy absorber is structured as a foam absorber including a compressible foam.
A displacement of the headlamp housing within the headlamp receiver activates the foam absorber which absorbs the greater portion of the transmitted energy. Besides compressible foam, however, other energy absorbing systems are also possible.
According to another preferred embodiment of the invention the headlamp housing has an elastic gasket against the housing receiver. Firstly, the elastic gasket seals the headlamp housing, which is open toward the rear, relative to the headlamp receiver, and secondly, to a certain extent, the elastic gasket acts as energy storage.
Nevertheless, most of the energy conversion occurs as plastic deformation of the energy absorber.
According to another preferred embodiment of the invention the headlamp housing hasxe2x80x94on its backsidexe2x80x94a first contact element that can be conductively connected to a second contact element seated on the housing receiver. The second contact element detaches from its seat when a defined impact occurs, and it can be displaced together with the headlamp housing along the energyabsorption path.
Damage to the contact element is prevented in that the second contact element also detaches from its seat when a defined impact occurs, and displaces along the energy-absorption path.
According to another preferred embodiment of the invention the second contact element is seated in a clip mount mounted on the housing receiver. Firstly, the clip mount permits easy assembly of the second contact element and secondly it allows the contact element to detach from its seat without damage.
According to another preferred embodiment of the invention the pins, or lugs, and the energy absorber are structured so that they are replaceable.
Replaceability of the pins and energy absorber permits trouble free repair after a crash involving the headlamps.